userlogrotate: Ensure we use a valid group name

Use user's primary group when user's name is not an existing group.

CHANGELOG.md

@@ -67,6 +67,7 @@ The **patch** part changes is incremented if multiple releases happen the same m
 * vrrpd: variable to force update the switch script (default: false)
 * webapps/nextcloud: Add Ceph volume to fstab
 * webapps/nextcloud: Set home directory's mode
+* userlogrotate: Use user's primary group when user's name is not an existing group
 
 ### Fixed
 

userlogrotate/files/userlogrotate

@@ -73,6 +73,9 @@ for path in ${SYSTEM_LOGS_SEARCH_PATHS[@]}; do
         for file in ${log_paths}; do
             user="$(user_for "${file}")"
             group="$(group_for "${file}")"
+            if ! getent group "${user}" > /dev/null 2> /dev/null; then
+                group="$(id -gn "${user}")"
+            fi
             rotate "${file}" "${group}":"${user}"
             delete_old "$(dirname "${file}")"
         done
@@ -85,6 +88,9 @@ for path in ${APPLICATIVE_LOGS_SEARCH_PATHS[@]}; do
         for file in ${log_paths}; do
             user="$(user_for "${file}")"
             group="$(group_for "${file}")"
+            if ! getent group "${user}" > /dev/null 2> /dev/null; then
+                group="$(id -gn "${user}")"
+            fi
             rotate "${file}" "${group}":"${user}"
             delete_old "$(dirname "${file}")"
         done